1. Technical Field
The present invention relates to an eye refractive power measurement apparatus which measures refractive power of an examinee's eye.
2. Related Art
There is known an eye refractive power measurement apparatus which projects measurement light onto a fundus of an examinee's eye, extracts the light reflected on the fundus as a ring image, causes a two-dimensional imaging device to capture this ring image, and measures eye refractive power, based on the captured ring image. In such an apparatus, a reliability coefficient is displayed on a monitor (refer to Patent Document 1). The reliability coefficient is obtained in such a manner that each of differences between a measured line, obtained by sequentially detecting an edge of the ring image per one degree over 360 degrees, and an elliptical approximation of the measured line is calculated, and these differences are added up.
The document that describes the related art is listed below.    Patent Document 1: JP 2007-089715 A (U.S. Pat. No. 7,452,078)
However, the conventional apparatus shows a displacement level in the entire eye by means of the reliability coefficient. Therefore, when a certain region has irregular astigmatism, it is difficult to specify this region having irregular astigmatism. Further, although there is a normal region where irregular astigmatism is not likely to exist, a low reliability coefficient is calculated due to the partial region having irregular astigmatism. It is to be noted that the same thing holds true for a case where a given region of a crystalline lens has cataract opacity.